*
    margin 0
    padding 0

body
    display flex
    flex-direction: row
    justify-content: center
    align-content: center
    height: 100vh
    overflow hidden
    
.container
    display flex
    width 90vw
    .panel
        height 80vh
        flex 0.5
        border-radius 50px
        color #fff
        cursor pointer //鼠标悬停时显示 “手型” 光标，提示可点击。
        margin: 10px
        position relative
        background-size cover
        background-position center
        background-repeat no-repeat
        transition all 700ms ease-in 
        h3
            font-size 24px
            position absolute
            left 20px
            bottom 20px
            margin 0
            opacity 0
            transition opacity 300ms ease-in 400ms
        // opacity 0
        &.active
            flex 5
            h3
                opacity 1

@media (max-width: 480px) {
    .container {
        width: 100vw; /* 修复：添加冒号 */
    }
    .panel:nth-child(4),
    .panel:nth-child(5) { /* 修复：用逗号分隔 */
        display: none;
    }
}